1. Technical Field
The present invention relates to a test apparatus, a demodulation apparatus, a test method, a demodulation method, and an electronic device. In particular, the present invention relates to a test apparatus, a test method, and an electronic device for testing a device under test that outputs an amplitude-phase modulated signal as an output signal, and to a demodulation apparatus and a demodulation method for demodulating the amplitude-phase modulated signal.
2. Related Art
Along with the increase in operating speed and circuit density of semiconductors, the amount of data transmitted within a semiconductor is also increasing rapidly. The amount of data transmitted within a semiconductor cannot keep pace with the necessary increases because of restrictions due to the number of pins, shape, wiring, and the like. Therefore, there is a large gap between the amount of data transmitted within a semiconductor and the amount of data transmitted outside the semiconductor.
To solve this problem, one proposal involves performing data transmission between semiconductors using an amplitude-phase modulated signal having a level and a transition point phase selected from among a plurality of levels and transition point phases according to the transmission data, as shown in Non-Patent Document 1. With such an amplitude-phase modulated signal, many bits of data can be transmitted in a single cycle, and so the gap between the data transmission amount inside and outside of a semiconductor can be decreased.
Non-Patent Document 1: Sunil Jain, “GHz Interconnects—Electrical Aspects,” International Test Conference NOTES Tutorial 3, US, Oct. 22, 2006, page 27
A test apparatus acquires from a device under test a binary signal that changes between H and L according to the transmission data, and compares the logic level of this binary value to an expected value. In other words, for each prescribed cycle, the test apparatus detects whether the signal is higher than a logic H threshold level or lower than a logic L threshold level at a designated first timing, and compares the detected results to the expected values. However, this test apparatus cannot achieve this detection for an amplitude-phase modulated signal whose phase and level changes every cycle, and so the test apparatus cannot test a device under test that outputs an amplitude-phase modulated signal.
Therefore, it is an object of an aspect of the innovations herein to provide a test apparatus, a demodulation apparatus, a test method, a demodulation method, and an electronic device, which are capable of overcoming the above drawbacks accompanying the related art. The above and other objects can be achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the innovations herein.